Bad computer or some other electrical problem?

[Huntervf]

Long story short, my wife hit a foot of standing water at 55 mph. Water went everywhere, SHO died. Towed it home, dried it out, runs but it's missing on a cylinder. Tried to run KOER / cylinder balance test but it's not running the diagnostic correctly. The KOER sequence will start (idle up, idle down) but won't give me the light for the goose test. And if I touch the gas for a balance test it just idles up.

Admittedly the plugs/wires have close to 100k on them, but all was fine before the bath. I removed the wires and dried them out/dried the plug wells, but never removed the plugs.

I'm not too savvy on electrical issues with the SHO. I did have a previous SHO that had problems with the diagnostic and it turned out to be a bad computer. I'm just wondering if the computer could be my misfire, or if there could be other electrical issues with CCRM/IRCM (I have no idea what they do, but I'm fairly certain they got very wet in this ordeal.)

Thoughts? I REALLY want to get this car back on the road so I don't have to relicense the Mustang and pull it out in the winter. But I also don't want to throw $500 for new DIS/plugs/wires/coil pack etc. because honestly, this car isn't going to be on the road much longer. Just getting too rotted underneath.

BTW, 93 ATX running a D4U1 computer, 205k. TIA for help!

 

[jmpSHO2nd]

Unless you can pull some codes which you are unable to do, the only thing you can do is throw parts at it. However if it was me I would definitely try a PCM first giay luoi nam. I might even have d4u1 around my shop somewhere if you want to try. Is it definitely misfiring?

 

[jimtash]

How much water was in the plug wells?

 

[Huntervf]

Yes it's definitely missing a cylinder at idle. It will occasionally pick it up and run on all 6 but it's only for a few moments. It seems to smooth out with RPM but I've not had a chance to go for a significant test drive so I can't say for certain if it's picking the cylinder up under acceleration or not.

#3 #5 and #6 plug wells were filled nearly to the top with water. I vacuumed the water out as best I could, blasted the wells with compressed air, then set a fan up in the engine bay for 24 hours. I also carefully blasted some air in the plug wires, and I was liberal with dielectric grease when I put it all back together. I did try and start the car right after I got it back to my shop and it was clearly missing multiple cylinders. The raw fuel smell almost had me thinking there was a fuel leak somewhere. When I put everything back together this evening I still had some trouble getting it to fire back up, but it didn't have anything like the raw fuel smell from before. Once I got it fired I ran it for about a half hour, including a short 1/2 mile drive. The engine smoothed out from the initial coughing, but it still had a noticeable misfire at idle.

 

[hawkeye18]

Future protip: The best way I've ever seen of drying plug wells out is... tampons. If you think about it for a second, you'll see why they're perfect. They also happen to slide right around the spark plug and get the water that paper towels and stuff can't. Or oil. Either way.

Also, you'll want to check the connectors at the DIS and make sure water didn't get in there. Ditto for the coil pack.

If the charcoal canister got wet, it will produce a fuel smell. I wouldn't worry too much about that.

I had a low rpm and idle miss that picked back up with RPM and it turned out to be the DIS. I would suspect that before the computer. They are really quite hardy.

 

[hawkeye18]

Also, FWIW, I have a coil pack and I'm pretty sure I have a spare set of wires I can send you.

 

[Huntervf]

Thanks for the part offers! I'm trying to see if any of the Michigan peeps has a D4U1--I'm traveling today in the SE MI area so hopefully one of them will get back with me. I suppose if I want to do some troubleshooting, I have Timbo's white 90 in my garage with a bunch of good parts on it

Naw, I can get a coil, DIS, plugs etc. all locally. It's just the computer that I can't. And I'd hate to do the swap only to find it's something else. Can anyone tell me about the CCRM/IRCM?

 

[jimtash]

Replace the plugs.

 

[luigisho]

Can anyone tell me about the CCRM/IRCM?

Tell you what? That's it's a bunch of relays or that you need to match the replacement with the original in the car designated by the letter on top? I remember a SHO going through a ton of water and it needed some time to get everything dry to track down the miss. Forget exactly, but I think plugs and wires cured it eventually.

 

[jimtash]

I'll add that whenever the CCRM gets wet on my car, the cooling fan and A/C compressor constantly run. I have to disconnect the connector at the compressor because the cycling switch won't stop it from running and literally, the lines will develop frost on them. Thinking you just need to let everything dry off and replace the plugs. The CCRM does strange things when it's wet.

 

[riden2low]

Did the same thing, went thru some water and got things wet. It was water in the coil pack. For me, it dried out in a few days. Didnt check to see if water was in the sparkplug wells in the rear but the front set was dry. I think from the heat of the engine running dried things out. But it will run pretty bad for a few days.

 

[TimboSHO]

Thanks for the part offers! I'm trying to see if any of the Michigan peeps has a D4U1--I'm traveling today in the SE MI area so hopefully one of them will get back with me. I suppose if I want to do some troubleshooting, I have Timbo's white 90 in my garage with a bunch of good parts on it

Naw, I can get a coil, DIS, plugs etc. all locally. It's just the computer that I can't. And I'd hate to do the swap only to find it's something else. Can anyone tell me about the CCRM/IRCM?

Seriously, I would try the DIS from the 90 to see if that helps. The computer and CCRM won't work. I don't have a D4U1, I only have the H3JZ or whatever it is from the 93 ATX if you need to try something.

I would take all of the electrical plugs apart on the DIS/Coil pack and make sure there isn't any water in there either. Take the wires off of the coil pack and make sure there isn't any water left there. It ran fine before, it's probably going to end up being water that hasn't dried out yet.

 

[luigisho]

Yes it's definitely missing a cylinder at idle. It will occasionally pick it up and run on all 6 but it's only for a few moments. It seems to smooth out with RPM but I've not had a chance to go for a significant test drive so I can't say for certain if it's picking the cylinder up under acceleration or not.

Any chance to run it and see if the miss is diminished? If I get the engine area too wet I usually throw a box fan under the hood with some twine to aim it down at the motor and let it run for a good while. Do that to cool it down for wrenching too.

 

[Huntervf]

Update--went ahead and replaced plugs and wires and all is well again. Should've just done that in the first place, but I was trying to be cheap And really it needed plugs/wires anyway; those had 95k and the plug gap had grown to .065!

And then I discovered that I'd pretty much burnt up the starter trying to get it started after the initial disassembly/dryout Had replaced it a year ago, found the receipt so just did a swap. No extra cost just a little more time on the cold concrete.

Now I need new idler pulleys... they're making quite a bit of racket! Or perhaps an alternator... better pull out the paperwork for the alternator I replaced in 2010!

 

[hawkeye18]

What's that they say about 90% of ignition issues are plug/wire related...?

 

[SHOdded]

What's that they say about 90% of ignition issues are plug/wire related...?

Surely not on the SHO! But gotta admit, rather be that than a crank sensor going every 5K